Sent in by Code Hunter at The Unofficial World of Nintendo!!!
When the move "Wrap" is used against you in battle, switch your
Pokemon after the first attack (in the succession of 2-5) hits you.
There will be no penalty to you for switching Pokemon (i.e. your
enemy does not get a free hit on you). Doing this stops the wrap
completely and gives you the chance to "choose your attack." If
the Pokemon you bring out is faster than the Pokemon wrapping
you, you will even get in the first hit.

Sent in by Code Hunter
To take pictures of Pokemon, go to the main menu where you can
select stadium, VS Battle, Battle NOW, or Gallery. Open up gallery
and scroll down the left side of the screen to snap picture of
Pokemon. Then, select your gamepack, or rental pack, and
choose what Pokemon you want to snap. Then, you can take
pictures of the Pokemon you selected. Move the camera angle
with the D-pad, and snap a picture with A. After about five seconds,
the Pokemon will do a special move.
EXAMPLE: Mew will spin around really fast, Flareon will turn around
and shake his butt at you. You can bring your pack to Blockbuster
and print out stickers if you want. Have fun with your camera!

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
During a battle your Pokemon has to be poisoned and have to have
at least low HP like 5 or 6 Hit Points and it must know fly. Have it
use Fly. When it faints from poison it will faint up in the sky like
how it does on the ground, sort of like an invisible ground in the sky.

To beat Mewtwo easily just get a level 100 Snorlax. Teach it
Self destruct. Then give Snorlax the max amount of Calcium and iron
and when you get to Mewtwo just Self destruct. Mewtwo should almost
die so just put in another guy with Self destruct and use it. I recommend
using Snorlax because Snorlax special is Self destruct!! Make sure Mewtwo
doesn't hit you with a critical hit though!

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
First catch a low level Pokemon that you don't mind getting rid of.
Next transfer all Pokemon, except the low level Pokemon you just
got, to the Pokemon boxes on Bill's PC. Next save in the Pokemon
center. Now on Pokemon Stadium go to the lab and transfer all the
Pokemon in the Game Boy Pokemon boxes to the N64 Pokemon boxes. Next
start your Game Boy game over. Once you can buy poke balls go to the
Pokemon center and save. Next go back to the Pokemon Stadium's
lab and move all the Pokemon in the N64 Pokemon boxes to the Game Boy
Pokemon boxes. Go back to the Game Boy game and you should have
all your Pokemon back, except the low level one, plus you can the
ones you need. You can repeat this code as needed.

To gain the "Hyper" difficulty for the CPU opponents in the Kids'
Club (minigames area), play "Who's The Best?" mode on Hard
difficulty. Set the number of wins needed to 5 or higher. You
must win 5 games (stars) in a row without losing once. Once you
manage to do this, a message will appear on screen saying that
the CPU can now play at "Hyper" difficulty. This is the mode of
difficulty you see on the demos if you leave it at the title screen
long enough. It's extremely difficult to win against these
super-players, but if you're looking for a challenge, go for it!

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
Get to Round 2, by beating Round 1 Mewtwo. In Round 2, go to 'Free
Battle', 'Prime Cup', or 'Gym Leader Castle'. Mew is accessible as
the last rental Pokemon in these three modes.

Sent in by Code Hunter
Here is a trick that will help you if the Pokemon you are fighting uses
Fly or Dig. After it has flew up high or dug a hole use Swift. Since it
is so accurate it will hit the Pokemon even though you are suppose
to miss it.

Sent in by Code Hunter
Beat R-1 mode and R-2 Mode (including Mewtwo). Once you do
that you are given a set of bonus stickers that you can access
in the Gallery Mode. Go to the Gallery main screen. When there
move the cursor to print and press and hold L and R. Once
you keep the buttons pressed for a while the Print option will
now change to Bonus. You now have 16 bonus backgrounds.

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
To get the special Amnesia Psyduck (that you can upload to Pokemon
Red/Blue/Yellow), register all 151 Pokemon in the hall of fame (on
Pokemon Stadium not Red/Blue/Yellow) and you will be awarded
Amnesia Psyduck!

Sent in by Code Hunter
Whenever you complete Gym Leader Castle, (actually, just the Elite 4 and
your rival) you can receive a special Pokemon to download to your
Pokemon game! These Pokemon consist of:
Eevee
Hitmonlee
Hitmonchan
Squirtle
Charmander
Bulbasaur
Omanyte
Kabuto
NOTE: These Pokemon are given at random every time you beat it.

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
Pika Cup: Pokemon can be between level 15-20.
Petit Cup: Pokemon can be up to level 30. Height limit of 6'8" and
weight limit of 44 pounds.
Poke Cup: You can only use 3 Pokemon (of levels 50-55). The sum of the
Pokemon's levels cannot exceed 155.
Prime Cup: All Pokemon allowed. Opponents are always level 100.

Sent in by Code Hunter
To get the Surfing Pikachu, use Pikachu as one of the 3 Pokemon that
battle in the Prime Cup, Master Ball Division. (You must beat Poke
Ball, Great Ball, and Ultra Ball Divisions) Also, it must be Round 2.
(after you beat all the cups) Make sure the Pikachu is YOUR Pikachu, not
a rented Pikachu. The other five Pokemon also must be yours. Beat
it, and you see a ending with Pikachu on a surfboard. Now you can
play the Surfing Pikachu in Yellow Version. (Your Pikachu cannot
know Surf, or this code won't work).

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
If you import your Pikachu form Red or Blue versions of Pokemon you
get a Pikachu with the general growl (also looks more aggressive), but
if you import your Pikachu from the Yellow version it will make the
Pika Pika sounds (and looks very happy).

Sent in by Code Hunter
To battle the strongest Pokemon, first you have to completely finish
all of the cups in Stadium Mode along with Gym Leader Castle. Night
falls on the stadium, and Mewtwo floats above, waiting. Move the
cursor over Mewtwo and press A to enter the battle. You may use
up to six Pokemon.

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
Dodrio Mode: Beat the Prime Cup (after you have already beaten the Poke
Cup). Speed is now even faster. By pressing C-Right during the game in
Pokemon Red, Blue, or Yellow, you can switch between Doduo and Dodrio Modes.

Sent in by Code Hunter
There is a secret R-2 Mode in Pokemon Stadium. After you have beaten
the Stadium and Gym Leader Castle Modes, beat Mewtwo. After the
credits roll, the R-2 Mode will be unlocked. It is much harder and has
new battles. You can toggle between R-2 and Regular Mode at the
start-up screen by pressing C-Right.

Sent in by Code Hunter at The Unofficial World of Nintendo!!!
The secret to the color variations lie in the names you give your
Pokemon as well as your trainer ID number (assigned to you in Pokemon
Blue, Red or Yellow, whenever you start a new game). While there
are a few secret names that change only certain Pokemon's colors,
there are a few naming tricks that result in different color
variations. For example:
Use only lower caps (ie: poliwhirl)
Reverse the syllables (ie: DRILLBEE)
Abridge the names (ie: Pika)